1. Technical Field
Methods and apparatuses consistent with the present invention relate to comfort/support analysis of a sleep support member and to determining whether the firmness of an identified sleep support member is acceptable. Among other things, methods and apparatuses consistent with the present invention relate to testing a sleep support member's firmness after the sleep support member is manufactured, but before the sleep support member leaves the manufacturing line. These methods and apparatuses also relate to determining whether customized sleep support members, which have been custom-manufactured to provide optimal support and comfort characteristics for a particular person(s), have been manufactured to desired specifications.
2. Description of the Related Art
A wide variety of different sleep systems are currently available. Such sleep systems may comprise all aspects of a bedding assembly including, but not limited to, mattresses, box springs, foundation units, bed frames, pillows, mattress pads, linens and, more generally, to any type of sleep product that influences a person's sleep. However, each respective sleep system may be suitable for some persons but not suitable for others persons.
It is particularly important for a mattress and/or a foundation unit to provide proper comfort and support for a person using the mattress and/or foundation unit. For example, a mattress may deliver support through the resistance provided by innersprings to the downward force applied due to the person's body weight.
However, conventional manufacturing methods cannot guarantee that a manufactured mattress will provide comfort and support characteristics for a purchaser within acceptable tolerances. Further, there is no way for a purchaser to know that a mattress that is delivered to the purchaser's home exhibits the same comfort and support characteristics as the mattress that the purchaser tested in the store. Thus, there is a need for an objective way for a consumer to determine whether a purchased mattress is acceptable.
Whether or not a mattress will provide proper comfort and/or support for an individual person can be determined by subjecting the mattress to a firmness test. This can be accomplished by using, for example, an Indention/Load/Deflection (“ILD”) test machine. An ILD test machine is a conventional device that tests the firmness of a mattress or a foundation unit by determining how far the surface of the mattress or foundation unit deflects when subjected to a certain force (i.e., load). Conventional ILD test machines take measurements at regular intervals (e.g., ¼ inch or one inch).
Although such conventional ILD test machines are sometimes used to approximate the firmness of a batch of mattresses or foundation units by testing one mattress or foundation unit from the batch at the design stage, there is no conventional system that allows testing of whether the firmness of each and every mattress or foundation unit that is produced in a manufacturing line is acceptable as each mattress or foundation unit is manufactured. Thus, there is a need for an in-manufacturing-line comfort/support analysis system. Such a system would (among other advantages) help to address the problem of ensuring that a customized mattress and/or foundation unit (i.e., a mattress and/or foundation unit that is custom manufactured to meet the specific characteristics of the intended user(s)) is suitable for use by the user(s). There is also a need for an improved comfort/support analysis system for research and development purposes.
Conventional ILD test machines have failed to address these problems and the prior art has failed to appreciate the aforementioned advantages. Indeed, conventional ILD test machines have not been employed in a manufacturing line for testing mattresses, much less for every mattress that is manufactured. Moreover, conventional ILD test machines are typically only used to determine a firmness value for a specific deflection and there is generally no comparison performed using the entire ILD curve (i.e., various loads vs. deflection values). However, mattresses and foundation units frequently do not exhibit a linear ILD curve (i.e., they do not behave with a constant force per unit length according to Hooke's Law F=−k·x).
Instead, the ILD curve of many mattresses and foundation units is more complex because many mattresses or foundation units are made of multiple components and layers that provide varying levels of firmness. For instance, the top portion of a mattress typically comprises comfort materials such as foam and fiber materials that exhibit a different ILD curve than the support layers comprising inner-springs that are disposed underneath the comfort layers.
Accordingly, an in-manufacturing-line comfort/support analysis system would be useful to manufacturers for warranty and quality assurance purposes and would allow manufacturers to ensure that manufacturing methods are correct. For example, an in-manufacturing-line comfort/support analysis system would allow manufacturers to guarantee that every manufactured mattress will provide comfort and support characteristics for a purchaser within acceptable tolerances. Such an in-manufacturing-line comfort/support analysis system would also provide customers with an objective way to distinguish mattresses.
Additionally, a comfort/support analysis system that employs a comfort/support analysis curve, instead of a single point of measurement, would provide a more accurate assessment of the sleep support member's characteristics. Moreover, measuring the comfort/support analysis curve while removing the testing platen from the mattress, in addition to measuring the comfort/support analysis curve while the testing platen is deflecting into the mattress, would allow analysis of the sleep support member's material recovery characteristics.